1. Field of the Invention
The present invention relates to a system which saves access logs, particularly relates to an access log storage system which saves access logs in a memory apparatus controlled by a file system.
2. Description of Related Art
In recent years, digital multi-function apparatus not only includes the functions as a copier but also other functions. Functions such as a document printing device having a hard disk drive capable to save document data to retrieve necessary data and to print them has become popular. The digital multi-function apparatus are capable of saving various kinds of electronic data since many functions are incorporated in a digital multi-function apparatus. However, the possibility that such saved data is stolen, falsified and/or destroyed by a malicious third party has increased. For this reason, a digital multi-function apparatus equipped with security functions to protect confidential documents and personal data has come popular.
Among these security features, there is a function to obtain access histories to protected data saved in the apparatus.
Specially, since the access history becomes almost always large volume of log data there is a log memory method which stores access history in a hard disk drive controlled by a file system. (For example, refer to Patent Reference No. 1).
Patent reference No. 1: Japanese Patent Open to Public, Tokkai 2002-140210.
Of course it is preferable that all access history to be protected should be memorized without any missing access event.
However, in many cases, to write data in a file is prohibited during initialization of the file system or initialization operation in many file systems commercially available. When an attack to the protected subject matter in a security system occurs during the initialization time period described above, the hard disk drive cannot receive commands from the log storage system. Accordingly, the fact that an attack has occurred is not memorized in the hard disk drive. For this reason, important log data of the security system cannot be saved and there is a possibility that the security system becomes frail.